What is the recommended treatment for cellulitis, especially when the nasal area is involved?

Treatment of Cellulitis of the Nasal Ala

For cellulitis involving the nasal ala, start with a beta-lactam antibiotic active against streptococci and methicillin-sensitive Staphylococcus aureus (such as cephalexin 500 mg every 6 hours or dicloxacillin 250-500 mg every 6 hours) for 5 days, extending only if clinical improvement has not occurred. 1, 2

Why Beta-Lactam Monotherapy is Appropriate

• Beta-lactam monotherapy is successful in 96% of typical cellulitis cases, confirming that MRSA coverage is usually unnecessary even in areas with high MRSA prevalence 2, 3
• The primary pathogens in typical nonpurulent cellulitis are β-hemolytic streptococci (especially Streptococcus pyogenes) and methicillin-sensitive S. aureus, which are adequately covered by first-line beta-lactams 1, 3
• Recommended oral agents include penicillin, amoxicillin, amoxicillin-clavulanate, dicloxacillin, cephalexin, or clindamycin 1, 2

Treatment Duration

• Treat for exactly 5 days if clinical improvement has occurred; extend only if the infection has not improved within this initial timeframe 1, 2, 4
• Traditional 7-14 day courses are no longer necessary for uncomplicated cases, as 5-day courses are equally effective 2

When to Add MRSA Coverage

You must add MRSA-active antibiotics if ANY of these specific risk factors are present:

• Penetrating trauma to the nasal area 1, 2
• Purulent drainage or exudate visible from the infection site 1, 2, 5
• Evidence of MRSA infection elsewhere on the body 1, 2
• Known nasal colonization with MRSA 1, 2
• History of injection drug use 1, 2
• Systemic inflammatory response syndrome (SIRS): fever >38.5°C, heart rate >110 bpm, or WBC >12,000/µL 1, 2

If MRSA coverage is needed, use clindamycin 300-450 mg orally every 6 hours as monotherapy (covers both streptococci and MRSA), OR combine trimethoprim-sulfamethoxazole or doxycycline with a beta-lactam 1, 2, 5

Critical Caveat for Facial/Nasal Cellulitis

• While the nasal ala is a facial location, do NOT automatically assume MRSA coverage is required simply because of the anatomic location 1, 2
• The evidence shows that typical nonpurulent cellulitis—even on the face—is predominantly streptococcal and responds to beta-lactam monotherapy 1, 3
• Adding trimethoprim-sulfamethoxazole to cephalexin provides no additional benefit in pure cellulitis without abscess, ulcer, or purulent drainage 2, 6

When to Hospitalize

Admit the patient if ANY of the following are present:

• SIRS criteria (fever, tachycardia, altered mental status, hemodynamic instability) 1, 2
• Concern for deeper infection or necrotizing fasciitis (severe pain out of proportion to exam, skin anesthesia, rapid progression, bullous changes) 1, 2
• Severe immunocompromise or neutropenia 1, 2
• Poor adherence anticipated to outpatient therapy 1
• Failure of outpatient treatment after 24-48 hours 2

For hospitalized patients requiring IV therapy, use cefazolin 1-2 g IV every 8 hours for typical cellulitis, or vancomycin 15-20 mg/kg IV every 8-12 hours if MRSA risk factors are present 2, 5

Essential Adjunctive Measures

• Elevate the head to promote gravity drainage of edema and inflammatory substances from the nasal area 1, 2, 4
• Examine for and treat predisposing conditions such as nasal trauma, eczema, or chronic edema 1, 2
• Consider systemic corticosteroids (prednisone 40 mg daily for 7 days) in nondiabetic adults to potentially hasten resolution, though evidence is limited 1, 2

Common Pitfalls to Avoid

• Do NOT routinely add MRSA coverage for typical nonpurulent nasal cellulitis without specific risk factors—this represents overtreatment and increases antibiotic resistance 1, 2
• Do NOT use doxycycline or trimethoprim-sulfamethoxazole as monotherapy, as their activity against beta-hemolytic streptococci is unreliable 1, 2
• Do NOT extend treatment beyond 5 days automatically—only extend if clinical improvement has not occurred 1, 2
• Do NOT delay reassessment—evaluate within 24-48 hours to verify clinical response, as treatment failure requires prompt adjustment 2, 5

If Treatment Fails After 48-72 Hours

• Immediately add empiric MRSA coverage with trimethoprim-sulfamethoxazole 1-2 DS tablets twice daily, doxycycline 100 mg twice daily, or clindamycin 300-450 mg three times daily 5
• Consider alternative diagnoses: abscess requiring drainage, deep infection, or cellulitis mimickers 2, 5
• Obtain blood cultures if systemic signs are present (positive in only 5% of cases but helpful when positive) 1, 5
• For hospitalized patients with treatment failure, switch to vancomycin 15-20 mg/kg IV every 8-12 hours 5